The correction amount is the radius of the copper wire + the discharge gap. The wire radius is a fixed value, and the discharge gap will vary with the discharge energy. The smaller the discharge energy, the smaller the gap, and the larger the discharge energy, the larger the gap. 

Electrical conductivity of working fluid
The processing fluid used by the wire cutting machine is divided into two categories, one is water, the other is oil, and the processing fluid used by the Qinghong wire cutting machine is water, so the effect of water on the processing is explained here. The so-called working fluid below refers to water.

The function of the processing fluid on the wire cutting machine
1. Reduce disconnection
It can cool the cutting line to help reduce the temperature of the cutting line due to electrical discharge machining. Lowering the temperature can effectively help the stability of the process and reduce the possibility of wire breakage.
2. Wash away machining chips
Water pressure can be used to squeeze out the residues and fine chips generated during processing to avoid short circuit due to processing chips, which is helpful for processing accuracy and processing stability.
3. Restore the insulation between the cutting line and the workpiece
Water has a resistance value that can help restore the insulation between the workpiece and the cutting line after discharge

Explanation of water resistance value
When electrical discharge machining occurs, an insulating material is needed between the cutting wire and the work object to make it discharge. On the Qinghong wire cutting machine, water is used as the insulating material, and the insulating properties of the machining fluid determine the machining accuracy and cutting The main reason for speed stability. Therefore, it is necessary to pay attention to the degree of water insulation, which is commonly known as water specific resistance or conductivity, and the displayed value and setting can be performed on the water quality test meter on the water tank.

Water resistance control method (pointer type)
Need to use the water quality inspection table located on the water tank to make settings.
The scale pointed by the pointer of the water quality inspection meter is the conductivity of the current water quality. If you move the MEAS up and hold the MEAS up, use SET to adjust the pointer to the water quality you want to set, and then the water quality will automatically maintain its set water quality until the resin Until it expires (the water quality setting can only be set to a higher value than the current water quality. If you want to reduce the water quality, you must first reduce the setting value and continue cutting for a period of time, and the water quality will slowly decrease to a new one Set value, or add new water.)

Operation instructions
1. If you press the SV button in the running mode, the green LED next to the SV button will light up, indicating that the water conductivity quality displayed is the set value, and the controller is in the SV SET / SAVE mode display, in this mode You can use the UP and DOWN keys to set the target value you want to set. After setting the target value you want to set, you must press the SV button again, and the set target value will be stored at this time. The green LED next to the SV button will go out (if the SV button is not pressed, the system will count down to save the target value), and then automatically return to the PV operation mode.
2. If you press the SV button in the running mode, the green LED next to the SV button will light up, indicating that the water conductivity quality displayed is the set value, and the controller is in the SV SET / SAVE mode display, in this mode You can use the UP and DOWN keys to set the target value you want to set. After setting the target value you want to set, you must press the SV button again, and the set target value will be stored at this time. The green LED next to the SV button will go out (if the SV button is not pressed, the system will count down to save the target value), and then automatically return to the PV operation mode.
3. When the set value is greater than the currently displayed value, the ion exchanger (after the delay time) will be activated (the WORKING light is on) until the displayed value is greater than or equal to the set value, the ion exchanger will not be turned off.
4. When the water level in the water tank is insufficient, the WATER LOW light will light up, and the start function of the ion exchanger will be forcibly closed at this time.
5. The controller has a memory function and will automatically record the last set value after the system is reset.

Principle of Water Ionization
The water flows through the ion exchange resin and mixes with the resin to produce a chemical effect to remove the metal ions mixed in the processing fluid, so that a certain water resistance value can be maintained.
If the water resistance value of the actual processing fluid is lower than the set value, the water tank will automatically start the ion exchange resin to control the conductivity of the water within the set insulation degree. The resin has its service life and will be affected after a long period of operation. As a result, the removal ability is reduced. If you continue to use it, it will not work to the set value. At this time, you need to replace the resin.
Recommended setting value of working fluid

Influence of processing fluid on processing
(1) When the conductivity is low (good electrical insulation) (high water specific resistance)
The discharge gap generated by the electric discharge is small, and the processing speed is slow, which is suitable for use when a good surface roughness is required.
Long-term setting of high water resistance will reduce the life of the resin.
(2) When electrical conductivity is high (poor electrical insulation) (water specific resistance is low)
In the narrow processing gap between the upper and lower ends, the electrode material will be attached to the processing and the upper size will be larger.
The discharge gap generated by the electric discharge is larger and the processing speed is faster, which is suitable for use when the accuracy is not required and the processing speed is fast.
It is easy to cause the reduction of the intermediate size of the processed object.
(3) When the conductivity is too high
If the machining fluid and the current flow are too much, the voltage between the electrodes cannot reach the discharge voltage, and the machining speed will be reduced a lot.
The electric current flowing through the processing fluid will cause electric corrosion of the processed material, causing discoloration and pinholes.
Specific resistance of work material
The electrical conductivity (kΩ/cm) of the processing material is generally used. Special items
SS material S45C, SK3, NAK55 40-60 NAH material is not easy to get a fine processing surface.
SKS3, SKD61SUS304 40-30
SKH9 40-60
Cu, Bs 10-20 In order to avoid galvanic corrosion, increase the specific resistance.
A1 10 or less will produce vaporized film, which is easy to form wire breakage. Try to avoid processing interruption and wire breakage.
AgW, GuW 10 or less
Gr 40-50 According to the grade of graphite, the processing difficulty varies greatly
WC 8-15 reduces the specific resistance. When high-speed processing is performed, a large amount of Cobalt (cobalt) will be dissolved, which requires secondary processing.
Below 4, the specific resistance is high, and the electrode is easy to adhere to. You can use MO Wire to avoid electrode adhesion.

Processing fluid temperature control
The temperature of the processing fluid has an absolute relationship with the accuracy of the workpiece, especially the corresponding relationship with the room temperature.
The reason why the temperature affects the workpiece is due to the principle of thermal expansion and contraction
for example:
A temperature increase of 1 ℃ will cause an elongation of 11.5 μm on the steel of 1 m. Others such as:
Copper Carbonate: 12 * 10-6 m (1 ℃, expansion per m)
Pure copper: 17 * 10-6 m (1 ℃, expansion per m)
For example, if the shape is 200 mm long, and there is a difference of 5 ℃ from the beginning of the processing to the completion of the processing, the difference is 12 μ for carbon acid steel and 17 μ for copper.
The mechanical system (especially the work load and the lower body part) must have temperature expansion and contraction, and for high-precision processing, the room temperature and liquid temperature must be controlled.
Therefore, when performing finishing, you must ensure that the drop between room temperature and water temperature is within 3 ℃, and the workpiece must be placed at the same temperature as the wire cutting machine for more than 2 to 3 hours, so as to reduce the accuracy caused by temperature changes. error.
The environmental temperature of the mechanical system is generally slow for 2-3 hours, so it is still a good way to warm up the machine before processing.

note:
1. The position of the wire cutting machine must be kept away from direct sunlight, and it must be placed in an air-conditioned place.
2. Be sure to use a water cooler and set the difference between the water temperature and room temperature within 3 ℃.
3. The location of the water cooler must be kept away from direct sunlight and well ventilated for heat dissipation. Please do not place it in the same room as the wire cutting machine to avoid rising room temperature.

The starting point (cutting point) selected during WEDM has a direct impact on the accuracy of the finished product. Since the starting point position will affect the deformation of the entire template, the starting point must be carefully selected before cutting the finished product.

Starting point size
The size of the starting point should take into account the size of the wire diameter of the cutting wire. Generally, it is more practical to use a 0.2 mm wire diameter cutting wire to calculate the size of the cutting hole at least 0.3 mm.

Starting point
When performing wire cutting, try to avoid cutting directly from the side of the workpiece, and it is best to make a starting point inside the workpiece.
It takes about 0.2 ~ 0.3 mm path from the start of cutting discharge to entering stability (at least the wire diameter needs to be completely separated from the starting point and entering the processing program). However, generally considering the template deformation problem, the auxiliary routing (from the starting point to the entering The distance of the finished NC program path) is set to 2 ~ 5 mm, which will help stabilize the accuracy of the finished product.

Template processing
Generally, the workpiece used for wire-cutting processing is usually heat treated (quenched and tempered), and its hardness usually reaches HRc58 ~ 62. However, if the heat treatment is inaccurate and there is residual stress, it may cause the workpiece to deform or crack during processing. The finished product fails, so please confirm the heat treatment of the workpiece itself before processing, and the workpiece to be processed should be placed in the same room temperature environment as the wire cutting machine. Try to keep the temperature of the processed object the same as that of the wire cutting machine.
If you are using a water-immersed wire cutting machine, keep the workpiece at the same temperature as the water temperature of the processing machine, so as to reduce the deformation caused by different temperatures.
Note: If the processed object is magnetic, please demagnetize it to avoid causing some parts on the wire cutting machine to malfunction during processing and affect processing.